Heater



FIG. 1 is a front perspective view showing the new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof;

FIG. 5 is a side elevation view thereof, showing the opposite side of FIG. 4;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a heater, as shown and described. 